Originally Posted by wavecrosschris
If you reversed the two wires wouldn't yours read correctly? or not at all?
No, it would read the same. 200 ohms reads the same no matter which direction you read it.
You need to adjust the gauge so that it sees 220 (or whatever it is) as full, and zero as empty, or vice versa. If there is no way of doing that, you either replace the gauge, replace the sender, or live with it.
Note that there are different standards for senders. At least two different resistance scales, and I'm not sure the polarity is the same on all of them (i.e. is it max or min resistance at full?)